float ScrollAnimator::computeDeltaToConsume(
ScrollbarOrientation orientation, float pixelDelta) const
{
FloatPoint pos = desiredTargetPosition();
float currentPos = (orientation == HorizontalScrollbar) ? pos.x() : pos.y();
float newPos = clampScrollPosition(orientation, currentPos + pixelDelta);
return (currentPos == newPos) ? 0.0f : (newPos - currentPos);
}
bool ScrollAnimator::scroll(ScrollbarOrientation orientation, ScrollGranularity, float step, float delta)
{
float& currentPos = (orientation == HorizontalScrollbar) ? m_currentPosX : m_currentPosY;
float newPos = clampScrollPosition(orientation, currentPos + step * delta);
if (currentPos == newPos)
return false;
currentPos = newPos;
notifyPositionChanged();
return true;
}
void ScrollableArea::setScrollPosition(const DoublePoint& position, ScrollType scrollType, ScrollBehavior behavior)
{
if (behavior == ScrollBehaviorAuto)
behavior = scrollBehaviorStyle();
if (scrollType == CompositorScroll)
scrollPositionChanged(clampScrollPosition(position), CompositorScroll);
else if (scrollType == ProgrammaticScroll)
programmaticScrollHelper(position, behavior);
else if (scrollType == UserScroll)
userScrollHelper(position, behavior);
else
ASSERT_NOT_REACHED();
}
void RootFrameViewport::setScrollPosition(const DoublePoint& position, ScrollType scrollType, ScrollBehavior scrollBehavior)
{
updateScrollAnimator();
// TODO(bokan): Support smooth scrolling the visual viewport.
if (scrollBehavior == ScrollBehaviorAuto)
scrollBehavior = scrollBehaviorStyle();
if (scrollBehavior == ScrollBehaviorSmooth) {
layoutViewport().setScrollPosition(position, scrollType, scrollBehavior);
return;
}
if (scrollType == ProgrammaticScroll && !layoutViewport().isProgrammaticallyScrollable())
return;
DoublePoint clampedPosition = clampScrollPosition(position);
ScrollableArea::setScrollPosition(clampedPosition, scrollType, scrollBehavior);
}
void RootFrameViewport::setScrollPosition(const DoublePoint& position, ScrollType scrollType, ScrollBehavior scrollBehavior)
{
updateScrollAnimator();
if (scrollBehavior == ScrollBehaviorAuto)
scrollBehavior = scrollBehaviorStyle();
if (scrollType == ProgrammaticScroll && !layoutViewport().isProgrammaticallyScrollable())
return;
if (scrollBehavior == ScrollBehaviorSmooth) {
distributeScrollBetweenViewports(position, scrollType, scrollBehavior);
return;
}
DoublePoint clampedPosition = clampScrollPosition(position);
ScrollableArea::setScrollPosition(clampedPosition, scrollType, scrollBehavior);
}
